“Therapists using the McKenzie method classify patients based on repeated end-range trunk movement tests into 1 of 3 main syndromes: derangement, dysfunction and posture.”
There is a lot here even though they summarized it very succinctly. By the by, one of the authors, Jason Ward, has an awesome podcast called the Mechanical Care Forum that you guys should all check out. He delves into the topics of Mechanical Diagnosis and Therapy mostly, but also has other guests on the show such as Stu McGill, Mulligan (no need for a first name) and others.

MDT is a systematic assessment process in order to classify patients into one of three categories. The derangement category has the hallmark sign of centralization and peripheralization. This is being taught in schools with much evidence to support it for good outcomes. RANT: When I was in school this was barely touched upon and MDT was only one of the methods that a person may be exposed to upon graduation. I recently visited Governors State University and was pleased to see that they have added centralization/peripheralization, directional preference and repeated movement exams into the curriculum. The derangement syndrome is classified by rapid change, for better or worse, either symptomatically or mechanically (range of motion, reflex, strength change, sensation changes). The derangement syndrome is the most prevalent syndrome classification in MDT.

The second most common syndrome is the dysfunction syndrome. This is further subclassified into two parts: articular dysfunction and contractile dysfunction. Starting with a contractile dysfunction, it is as simple as the name denotes. It is a dysfunction of some of the contractile tissues of the body and is named for the direction of dysfunction. For instance, if there is a “muscle strain” of the shoulder flexors, the patient would demonstrate with pain during contraction of the muscle with pain increasing with increasing load and also pain during the stretch of this muscle. This is a contractile dysfunction into shoulder flexion.

One could also have an articular dysfunction, which is a dysfunction of non-contractile tissues. This could be any structure that doesn’t contract, but the joint capsule is one of the structures typically referred to. A deficit in the non-contractile structures should cause a joint to be limited in its range, but not with regards to its strength. The hallmarks of the dysfunction syndrome are both a lack of dramatic change and consistency with regards to the limitation.

I wrote a case series a couple years back that I am working to get published regarding cancer causing back pain. This would be an “other” category. It doesn’t fit one of the 3 presentations and would have to be classified as other and wouldn’t fit into the treatment paradigm for MDT.

“Within the McKenzie classification system, evidence supports the prognostic relevance and discriminative utility of 2 pain-pattern classification criteria: centralization and directional preference…Briefly, centralization is characterized by spinal pain and referred spinal symptoms that are progressively abolished in a distal-to-proximal direction in response to therapeutic movement strategies. Directional preference has been defined as a specific movement or posture that decreases the patient’s pain, with or without the pain having changed location, and/or increases the patient’s lumbar range of motion”

Where to start? Centralization…there has been much work by Werneke and Hart regarding centralization’s prognostic value for both positive and negative. Also, Skytte 2005ish has an article that reveals that a lack of centralization leads to a 600% increase in the need for invasive procedures. https://www.ncbi.nlm.nih.gov/pubmed/15928538

If you don’t know the story behind Mr. Smith, I will tell it to the best of my recollection. Robin McKenzie, the founder of MDT, had a patient come into the clinic in New Zealand in the 1950’s with back pain that radiated into the leg. Mind you, patients at this time were only performing flexion based exercises (knees-to-chest or chest-to-knees) and extension based exercises (back bends or press-ups) were thought to sever the nerves of the spine if one performed the exercises too aggressively. Hence, they were avoided. Walks in Mr. Smith. Robin was a great therapist and thus he was also a very busy therapist. Robin told Mr. Smith to go into the room and lie down on his belly, forgetting that he had the table positioned in such a manner that the head of the bed was elevated. What this means is that when Mr. Smith was on the table, he was in extension. Robin was so busy in the clinic that he was unable to get to Mr. Smith immediately. In essence, Mr. Smith spent a prolonged period of time in extension. His symptoms rapidly abolished in his leg and he only had back pain remaining. Robin saw this and made an attempt to understand the phenomenon. This lead to 50 years of studying pain patterns until the dynamic disc theory was finally being confirmed in the research. Mr. Smith and Robin effectively changed the way that spines are treated and because of this, Robin was ranked the most influential therapists in the 1900’s by the orthopedic section of the APTA.

Directional preference was termed by Dr. Ron Donelson, also author of Rapidly Reversible Back Pain (a good read, but at times boring). A person can have a directional preference in the absence of centralization. There may be a change in mechanical responses prior to a report of centralization, also there are studies documenting directional preferences in joints outside of the spine.

“…retrospective analysis of a longitudinal, observational cohort was conducted”

This is fancy speak, but the words are important. This means that the researchers observed what happened over the course of time (observational longitudinal), but the information is from a time period prior to actually initiating the study (retrospective). The reason why it’s important is because patient consent is not needed for this type of study, since the treatment was unchanged from what a therapist would do compared to an interventional study in which a person is trying to prove or disprove something is effective.

“Patients were classified at intake into the subgroups of centralization, noncentralization, or not classified…using a body diagram”

Not all patients will centralize at the time of the initial evaluation. If they do centralize and remain centralized, this is a great sign, but some patients may require up to 7 days in order to centralize, as noted by one of the Werneke studies.

“Treatment processes were guided by the patient’s symptomatic and mechanical responses to continual assessments of repeated movements, positioning, and/or manual techniques. If centralization or directional preference was observed, treatment was standardized following MDT assessment and treatment methods.”

The problem with this system is that it is elusively easy to use. If during the session, we find movements, positions, or postures that make your symptoms worse, we educate you to discontinue or avoid those positions TEMPORARILY. When we see a directional preference or centralization, we tell you to go forth and do those movements that cause good things to happen. That’s it. For someone well trained, we can find a directional preference in most patients. For those that aren’t trained…well…the system may not work, which is a bummer for the patient because it’s not the systems fault.

Classifying a patient demonstrates improved results compared to not classifying patients. Although this may be a small improvement over other factors that could predict outcome, it is still better than not classifying. When you go to see a therapist as a patient, you want to know how they are classifying you. As a student, you want to know how sophisticated the clinical instructors classification system is. A therapist that is performing interventions because of tradition is not using a good classification system.

“…therapists with the highest level of McKenzie training (diploma in MDT) achieved significantly better FS (functional) outcomes compared to therapists who did not have a diploma in MDT”

This won’t offend me. I don’t have a Diploma in MDT and personally know many therapists that have earned this distinction. It takes time to complete, a lot of money and time off of work/away from family in order to complete the diploma. If one has access to a therapist with this distinction…please go forth and get assessed.

Look…there are a lot of therapists that say that they “use McKenzie” in their treatment. Be wary of these therapists. McKenzie is not a treatment intervention, but an assessment process. If the therapist doesn’t have the initials denoting passing a certification exam or diploma exam, he/she is not using MDT at even a competent level.

“…the new physical therapists may lack the entrepreneurial spirit, skill and knowledge required to build their practice. Despite the size of a practice, time and effort dedicated to educating physical therapists new to the practice on how to develop a following should be implemented.”

I think that this holds true for any company. We should always groom those that work for the company in order to assist them with progressing their career. For instance, when I worked for Sam’s Club, I was consistently put into situations that would allow me to be more and more independent. In private practice, I was consistently left alone in the clinic run the clinic. At the hospital, there has been stagnation. I have no additional responsibilities given to me than I had when I started. This is one of the reasons that I am contemplating starting a new journey. I already have a following, but this does not translate into any more than simply being a practicing clinician. I can offer so much more.

“Send birthday or holiday cards…be active on social media…set reminders to contact patients at certain periods post-discharge…offer gift certificates to local coffee shops as a way to thank past patients who refer friends…offer a 1-year checkup consultation”

All of these are great ways to establish a following. I recently started this blog with the intention of building my brand. I am experimenting with how to reach the largest amount of people with the blog. As I continue through the months, I want to give this a 1-year trial period to see if consistent posts will bring more readers to the blog. I have a feeling that it won’t work, but I am willing to give it a try.

“Volunteer for local nonprofit organizations…provide free screenings, support local sports teams…offer your expertise to vendors.”

Again, all good ways to build a clientele. The best way to build a clientele in my opinion has yet to come up in this article. Provide excellent care that is patient focused. As hard as it is to get a patient in the door in today’s market of super chain PT clinics, hospital-based PT clinics, and Physician Owned PT clinics, it is vital that the private practitioner provide great service that separates him/her from a profit driven corporation. Physical therapy has decreased in profitability over the years (assuming that it is one therapist per one patient), but it continues to make money in the outpatient setting. The only way to make money is to gain the trust of patients by demonstrating that the therapist has the patient’s best interest at heart. I’ve seen all of the above put into action in a small private practice and in the end, it made the patients feel like a dollar sign. The patient’s realized that there was a primary reason for all of the above tactics, and it wasn’t to help the patient get better. This has to be the over riding theme of any marketing tool that we use. When I give community education speeches, I don’t care if the patient comes to me for future treatment. I care that the patient walks out the door with more knowledge than they walked in with. When I take a student, I care that they are better clinicians on the final day that the first day. This is how I have built my reputation in the community and as a clinical instructor.

“Strategically developing relationships with referral sources will lead to patients being directed to specific physical therapists due to their ‘expert’ knowledge and skills”
I question this last statement. I would love to believe that a physician would continue to refer to me when I leave the hospital based setting, but I realize that some people are beholden to others. I can’t blame them, but the system is broken. A patient has the right to go to therapy wherever he/she would like. This has to be the first thing that the patients understand. From here, a recommendation should be made, but the patient needs to know that they have the final say. I have a large patient base and there are many physicians that refer to me, but I tell the patient that they have a choice to see someone closer to home and sometimes I will go so far as to direct them to a therapist closer to home if I don’t feel that I have the special sauce needed for this patient. I have a specialty. I have talents, but if the patient is someone that has the ability to get better with most therapists, then I would rather them not be inconvenienced to drive more than 30 minutes to get to me. This may make for a worse business model, but my primary driver is patient care not the almighty dollar. I have done well for myself financially using this model and hope that it will continue to carry forward in private practice when I choose this model.

If there are any questions, comments, concerns or good jokes, please feel free to post them at my facebook page or comment on this blog.

How does the disc move?
“Clinically, disc herniation is most commonly observed posteriorly or posterior-laterally”

Very rarely does the disc herniated straight backwards (posteriorly). There is a very strong ligament at the back side of the spine that prevents a posterior herniation. The material in the disc will typically make a trough in the disc and go sideways from that point.

“Specifically, when the spine is loaded asymmetrically, the nucleus tracks along a radial fissure formed in the contralateral corner of the disc suggesting that annular delamination is load/direction dependent.”
When the spine is loaded asymmetrically is similar to bending sideways. Picture the spine as a bunch of books loaded on top of each other with big bars of wet soap in between. When you bend to the right, you would bring the right sided edges of the books closer together (i.e. they would be compressed) and the left side of the books would be gaped open (i.e. they would decompress). If there is a wet bar of soap in the middle, it would move away from the compressed side. This is what the above sentence is saying in a lot of words. There is more to it than this, such as forming a trough, which is similar to the annular fissure.

The disc is composed of two separate parts: the annular rings and the nucleus. The annular rings are a cartilaginous protector of the nucleus. It’s similar to putting Play Do in a sealed freezer bag. When you push on one end of the freezer bag, the play do goes in the opposite direction. This holds true for most discs. There is a study (I have trouble remembering the name, but its by a Japanese author…I’ll try to find it and write a post on it) that demonstrates that as the discs age and dehydrate, they may not always move away from the compressed side, but this is a different story for a different day. Just know that for the most part, most discs operate like this on most days.

“Callaghan and McGill (2001) determined that posterior disc herniations are consistently created with repetitive flexion under modest static compressive forces”

McGill…Oh great guru of spines…has done much research regarding the biomechanics of the spine. Stu, as he likes to be called, is actually very approachable and responsive to e-mails, which is surprising considering how high profile he actually is in the rehab world. Anywho…what they found was that a disc herniation is predictable with specific forces. If one repeatedly bends forward while standing and does this bending from the spine (NO-NO) instead of from the hips.

“Their data suggests that disc herniations are an injury that result from cumulative bending trauma and can initiate after only 5870 cycles of flexion/extension while under a compressive load of only 867N.”

It’s funny that they use the term “only 5870 cycles”. That’s a whole heck of a lot of flexion/extension cycles. This is more of the case of the straw that broke the camel’s back more so than one cycle of flexion/extension. The number that the authors gave for force is equivalent to about 200 pounds. Now take your upper body weight plus any external weight and this is the number of flexion cycles that it would take to cause a herniation.

“Bending the motion segments about an axis oriented 30 (degrees) to the left of the sagittal plane flexion axis resulted in the focused nucleus tracking toward the posterior right side of the disc in 15 of the 16 trials”

What this means is that in a majority of people, bending towards one direction will cause a movement of the disc material in the opposite direction. The are treatment strategies that are based on this exact theory.

“Discovering that the side that the nucleus tracks is dependent upon the direction of bending motion is of use in understanding injury mechanics”
This means that we could reverse engineer the injury if we have a picture of the disc. It also means that we could reverse the injury if the disc is still intact by moving in the opposite direction of the problematic motion. These are theories of course, but this type of theory is used in treatment.

NOTE: This article uses a porcine disc model, which is commonly used in the research to mimic the motion of the human disc.